Incident angle and energy dependences of low‐energy Ar+ ion sputtering of GaAs/AlAs multilayered system

Dependences of the depth resolution in Auger electron spectroscopy sputter‐depth profiling of a GaAs/AlAs superlattice reference material on the incident angle and energy of primary Ar⁺ ions were investigated. The results revealed that the depth resolution is improved for the lower primary energy as a square root of the primary energy of ions at both the incident angles of 50° and 70° , except for 100 eV at 50° , where the significant deterioration of the depth resolution is induced by the preferential sputtering of As in AlAs, and the difference in the etching rate between GaAs and AlAs. The deterioration of the depth resolution, i.e. the difference in the etching rate and the preferential sputtering, observed for 100 eV at 50° was suppressed by changing the incident angle of ions from 50° to 70° , resulting in the high‐depth resolution of ～1.3 nm. The present results revealed that the glancing incidence of primary ions is effective to not only reducing the atomic mixing but also suppressing the difference in the etching rates between GaAs and AlAs and the preferential sputtering in the GaAs/AlAs multilayered system. The results also suggest that careful attention is required for the optimization of conditions of sputter‐depth profiling using GaAs/AlAs superlattice materials under low‐energy ion irradiation. Copyright © 2009 John Wiley & Sons, Ltd.